1. Field of the Invention
This invention relates to a process for removing metals from water. In particular, this invention relates to a process for removing metals from water such that the processed water can meet the requirements for discharge into a natural stream.
2. Description of the Prior Art
Metals, such as mercury, lead, chromium, cadmium, silver, zinc and copper, can contaminate ground water when emitted in waste water from industrial buildings or in coal pile runoff from a steam plant. Since such metal-contaminated runoff from industrial processes frequently constitutes a considerable amount of water, an economical process is needed for removing such metals from waste water. Such a process could be useful in industry for treating water from coal washers, coal mines, steel mills and other industries having waste water contaminated with metallic ions in amounts exceeding environmentally safe levels.
Attempts to treat metal-contaminated waste water using ion exchange resin processes have not been as economical or efficient as desired due to the relatively high levels of metal contaminants which tend to decrease the absorption capacity and consequently the useful life of the ion exchange resin. There is a need for an improved process for removing metallic ions from waste water. There is also a need for a way to optimize the efficiency of an ion exchange resin process for removing metals from waste water on an industrial scale.